草莓镶脉病毒粒子提取及电镜观察

Extraction and TEM Analysis of Strawberry Vein Banding Virus Particles

从受感染的草莓（Fragaria sp）植株中提取了草莓镶脉病毒（Strawberry vein banding virus,SVBV）粒子并对其进行了电镜观察.用CTAB法从草莓叶片中提取总核酸,设计SVBV外壳蛋白基因特异性引物,利用PCR方法对杭州地区的草莓镶脉病毒感染情况进行检测.检测结果表明,在杭州地区大田种植的草莓中存在SVBV感染现象.从4株受感染草莓植株中分离克隆了SVBV的CP基因片段并测序;序列比较分析发现它们与已报道的美国SVBV分离物的CP基因（序列号NC_001725）核苷酸同源性为91％.利用差速离心法从上述草莓植株的叶片中提纯SVBV病毒,在透射电镜下观察到SVBV病毒粒子呈球形,直径约为40-55 nm.

Strawberry vein banding virus （SVBV）particles were extracted from the infected strawberry plants and analyzed by transmission electron microscope （TEM）.The total nucleic acids from strawberry leaves extracted by CTAB were used as template to amplify SVBV coat protein gene fragment by PCR with gene-specific primer.The results showed that strawberry plants planted in the field in Hangzhou were found to be infected by SVBV.The fragments of SVBV CP gene amplified from 4 infected strawberry plants were cloned and sequenced.Compared with the American SVBV isolate reported （GenBank accession number：NC_001725）,the sequences of coat protein gene of these isolates had 91％ identity.The purified SVBV was obtained from the infeeted leaves using differential centrifugation.Analysis of TEM showed that the diameter of purified virions ranged from forty to 40-55 nm.